Fuel injector pump



June 4, 1957 c. A. GONGWER FUEL INJECTOR PUMP 3 Sheets-Sheet l FiledFeb. 4. 1955 iii NF wk.

IN VEN TOR. CALVIN A GOIVGWER A T TORIVEY June 4 1957 c. A. GONGWER FUELINJECTOR PUMP Filed Feb. 4, 1955 3 Sheets-Sheet 2 53 7 49 ll 57 I T 8INVEN TOR. CALVIN A GONGWER A T TORNE Y June 4, 1957 c. A. GONGWER 3Sheet s-Sheet :s

QALVIN 0 R ATTO United States Patent FUEL INJECTOR PUMP Calvin A.Gongwer, Glendora, Calif., assignor to Aerojet- General Corporation,Azusa, Calif., a corporation of Ohio Application February 4, 1955,Serial N0. 486,120

4 Claims. (Cl. 299-.107.6)

This invention pertains to fuel injection, and more particularly to anintermittently operating injector pump which is self-cycling.

There aremany known varieties of fuel injector pumps and meteringdevices which act to inject quantities of liquids into such means fortheir use as combustion chambers. Generally speaking, these pumps arenot selfcycling; that is, their periodicity of operation is ordinarilydependent upon conditions in related apparatus, such .as cams to movecontrol elements in the pump, or chambers responsive to engine cylindercompression and the like. In addition, these existing devices allow forrelatively little adjustment of the quantity of fuel contained in eachpulse, the amount passing through at each actuation depending largely onthe geometry of the system. In the absence of an accumulator, dischargeis ordinarily limited to the amount which enters the fuel supply line atsupply pressure during the period the pumps discharge port is open.

Since such devices rely on other components, they are necessarilycomposed of more parts than if self-contained, and are therefore complexand provide extra opportunities for breakdown.

An object of this invention is to provide a pulse-type fuel injectorpump capable of injecting liquids (which may be molten metal if desired)into such means as a motor cylinder, in which the frequency of pulsationof injection and the quantity of fuel per injection can be cont-rolledby simple pressure adjustments, and which is not dependent upon externaldevices for its cyclical operation. For example, this invention has nonecessary interconnection with rotating, commutating or-reciproeatingmeans for its timing or quantity adjustments. An additional object is toutilize the pressure of the fiuid fuel itself for actuation of the pump.

A feature of the invention resides in a pintle assembly whichcustomarily closes an injection orifice discharging from a fuel chamberin the injection pump, and an accumulator for building up fuel pressureand volume, whereby the pintle is lifted from the injector orifice whenthe forces holding the pintle down are slightly more thancounterbalanced by fuel pressure tending to lift the pintle, and theaccumulated fuel is discharged from the injector jet. When the pressurefails in the fuel chamber after discharge, the pintle is again seated,and the abovedescribed steps are repeated automatically withoutdependence upon any other mechanism. By constructing the injectororifice of such size that pressure falls relativeyl slowly in the fuelchamber, the pintle assembly is caused to rise quickly.

An additional feature resides in the means for controlling the frequencyof pulsation, which comprises a simple valve regulating the flow of thefuel to the accumulator.

Still another feature resides inmeans for causing the pintle assembly toremain in its customary position, thereby closing the orifice whilepressure builds up in the 2,794,682 Patented June 4, 1957 accumulator.In cooperation with the accumulator these means determine the quantityof fuel in each pulsation. One such means is a substantially constantfluid pressure exerted as the pintle assembly to force it toward theinjection orifice. As alternate means, the pintle assembly may be springloaded so as to tend to remain in its customary position.

These and other features of my invention will be fully understood fromthe following detailed description and the accompanying drawings, ofwhich:

Fig. 1 is a plan view of an injector and accumulator according to theinvention;

Fig. 2 is a cross-section view of the accumulator;

Fig. 3 is an end view taken along line 3-3 of Fig. '2;

Fig. .4 is an end view taken along line 4-4 of Fig. 2;

Fig. 5 is a cross-section view of the injector;

Fig. 6 is an end view taken along line 66 of Fig. 5;

Fig. 7 is a cross-section view taken along line 7-7 of Fig. 5.;

Fig. .8 is across-section view taken along line 8-a8 of Fig.5;

'Fig. 9 is across-section View taken along line 9-9 of Fig. 1 showing aT connection between the injector, "accumulator and supply line indetail; and

general orientation and relationship between the components of aninjection device according to the invention. Anaccumulator 10 is joinedto an injector 11 by a conduit 12 having a T joint 13 in its length. Afuel supply line 14 extends from the T, and is therefore fluidlyconnected with conduit 12. A frequency control valve 15 is placed in thefuel supply line. This valve may be of any appropriate variable orificedesign.

The injector 11 is shown in detail in Fig. 5, and has a body or cylindermember 16 which encloses a fuel chamber 17, heater cavities 18,injection jet 19, injection nozzle .20, and an opening 21 by the nozzle20. The body is a central shaft housing 27 which expands to form acylinder 28. A lubricant passage 29 with a fitting 30 threaded thereinleads from the outside of'the cylinder member to the shaft housing.Fitting 31 connects with a further lubricant passage (not shown)permitting a silicone type lubricant to flow therethrough.

A vent passage way 32 connects the outside of the unit to the inner endof the cylinder 28, and a fitting 33 allows connections to be madetherewith. As best shown in Figs. 6 and 8 two additional fittings 34 aredisposedat the end of coolant passages in the cylinder member. Passages35 are drilled parallel to each other and into the member, and anintersecting passage 36 connects the two so as to form a continuousfluid conduit. A stopper 317 is inserted in passage 36 to blank off theun-needed length of conduit. This provides for steady circulation ofcoolant through the passages.

An end plate 38 having a central tapped passage '39 and holes 40matching threaded recesses 41 in the cylinder member is attached to thecylinder member by capscrews 42. The central tapped passage 39 leads tothe outside end of the cylinder 28.

A pintle assembly 43 comprises a piston 44 within the cylinder having aresilient ring 45 in a groove 46 around its periphery to inhibit gasleakage thereby, and a shaft 47 affixed to and depending from thepiston. The shaft 47 passes through the shaft housing 27 so as to beaxially slidable therein, and has a tapered seat portion 48 onthe end ofthe shaft inside the fuel chamber 17. The tapered seat portion faces theinjection jet.

As will be appreciated from Fig. 5, when the pintle is seated, theprojection of the area of the shaft remaining inside the fuel chamberand facing the jet onto a plane perpendicular to the axis of the shaftis greater than such a projection of any other part of the shaft facingin the other direction within the fuel chamber, that is away from thejet. In this manner, while the pintle assembly is seated, any pressurein the fuel chamber will tend to unseat it by forcing it away from thejet. An annular seat member 49 having a sloping shoulder 50 at the endadjacent the fuelchamber is threadably inserted in the injector orificeas a convenient means for sizing the jet. The shoulder 50 has asmaller'outer diameter than the tapered seat portion 48. 7

Since this injector device may be used to handle molten metals, lithiumfor example, means are provided for heating the injector. These meanscomprise resistance units 52 which are fitted into the heater cavities18. Leads 53 connect with buss bars 54 separated from the pump and fromeach other by layers 55 of insulating material. A flanged end plate 56is held to the body by screws 57, and electrical leads 58 pass throughthis plate to the buss bars. The buss bars, insulation, and leads may befastened to the body by means such as screws 59.

The accumulator is of a springing type, such that the volume of fluidtherein increases as the pressure increases. It comprises a circularshell 61 having a barrier 62which form's compartments 63, 64 at oppositeends of the shell. Fluids for the injector do not enter compartment 63.A disc-shaped resistance type heating element 65 is fitted intocompartment 63, and is held there by a plate 66 which is itself retainedby a snap-ring 67 in groove 68. Electrical leads to the heating elementpass through fitting '70, and are attached to the element by studs 71. 7

Compartment 64 has a bellows assembly 73 therein. This bellows assemblycomprises a flanged member 74 to bear against shoulder 72 in the shell,and a flexible bellows 78 attached to the flanged member. An end plate77 caps the end of the bellows away from the flanged member. Thisbellows has elastic properties which tend to diminish its length whenpressure inside it is decreased. Reinforcing rings 76 are insertedbetween each convolution of the bellows. These reinforcing rings alsoact as guides and can bear against the wall of the compartment 64,as thebellows expand or contract. An annular insert 79 having heater cavities79a fits within the bellows and has a fluid conduit 80 through itscenter to an expansion chamber 81 within the bellows assembly.Resistance heater elements 82 are placed in the cavities 79a, theirleads 83 entering through a fitting 84 and a passage in a retainerplate. 85. This retainer plate bears against the annular insert 79,which in turn bears on the flange member 74. The retainer plate is heldin place by snap rings 86 which are fitted in grooves 87 in the shell.The fluid conduit 80 continues through the retainer plate, and attachesto conduit 12.

Fuel supply line 14 and conduits 12 are interconnected by a T 13 ofconventional manufacture. The T has two' aligned side ports 88 forattachment to conduit 12, and a third port 88a for connection to thefrequency control valve 15.

A quantity control valve 89 interconnects a source of fluid pressure(not shown), with passage 39 and the cylinder 28 in the fuel injector.The source of pressure may be from the fuel supply itself, or liquid orgas from a system under pressure. This valve is of a pressure regulatingtype which maintains a substantially constant fluid pressure in thecylinder.

Fig. 10 shows an optional quantity regulating means, in which thecylinder 28 may be provided with a spring 90 between the piston 44 and acap 91 which is threadably engaged to the injector pump. By screwingdown thecap, the spring maybe preloaded as desired to vary the pressureon the pintle assembly.

The operation of the device will now betdescribed. Quantity controlvalve 89 is first opened to admit a fluid under pressure into cylinder28. This source might be such as a flask of pressurized nitrogen.Preferably it should be a fluid which would not react with the fuel inthe fuel chamber 17 in case of leakage through the shaft housing 27.This pressure will force the pintle assembly down to its customaryposition where the tapered seat portion bears against shoulder 50 toclose the injection jet 19. At this position, an outer annular ring onthe face of the tapered seat portion 48 remains inside the fuel chamber,while the central part of the seat portion 48 is sealed off from thefuel chamber and stands within the injection jet 19.

The net force with which the pintle assembly is held in the customaryposition is equal to the product of the area of piston 44 facing awayfrom the injection jet times the pressure in cylinder 28, less theproduct of fuel pressure in chamber 17 times the area of the projectionof the annular portion 48 within the fuel chamber 17 on a planeperpendicular to the axis of the shaft 47. This net force may beadjusted both by varying the pressure in cylinder 28, and by varying thefuel pressure in fuel chamber 17. 7

Electric current to the heaters is turned on so as to avoid freezing offuels in the pump if fuels are used which have a melting point higherthan ambient temperatures. Lubricant flow, and coolant flow are alsostarted at this time.

To begin the cycling action of the injector, frequency control valve 15is opened. The accumulator and fuel chamber will then begin to fill withfuel, and the pressure therein will rise. The elastic accumulator beginsto yield, and chamber 81 expands, thereby permitting the build-up ofboth pressure and volume therein. The upper limit of the pressure isthat maintained in the fuel supply line on the supply side of the valve.

As the pressure builds up in the accumulator and fuel chamber, the netforce tending to seat the pintle assembly on the shoulder 50 decreases.So long as the force on the piston in cylinder 28 is greater than theforce tending to unseat the pintle, the injection jet remains closed.When the latter force is slightly greater, the pintle assembly will beunseated. At this moment, the central part of the tapered seat portion48 becomes exposed to pressure in the fuel chamber, and the unseatingforce is increased.

This increased force causes the pintle to snap away from the jet.

When the pintle assembly is unseated, some of the fuel stored in theaccumulator can flow to the injection jet, along with the quantity offuel which passes through the supply line 14 during the period the jetis open.

The entire tapered seat portion 48 remains exposed for a time, becausethe pressure in chamber 17 does not fall suddenly. This results from thefact that the injection jet opening is relatively small compared to thesize of the conduits 12.

This fuel ejection, being that of pressurized fluids escaping from achamber after a quick valve opening, is in a burst. However small theinjection jet may be, it still permits fuel to escape more rapidly thanthe frequency control valve 15 permits fuel to enter. Therefore, whensome of the fuel accumulated by pressurizing the accumulator leaves theaccumulator, the pressure therein falls so that the force resulting frompressure in the cylinder 28 can move the pintle assembly to close thejet 19. The described cycle then automatically starts again.

It will now be understood how the frequency of pulsation is determinedby the valve 15. The accumulator must be charged along with the fuelchamber 17. The pintle assembly does not operate before the pressurereaches some predetermined value. This charging takes a finite length oftime, during which period the pintle assembly closes off the injectionjet. The more open the valve is, the more quickly the pressure willbuild up in the fuel chamber. Thus the rate of flow through valvedetermines the frequency of pintle operation (assuming a constantpressure in chamber 28). The frequency adjustment is as simple asturning a valve.

The quantity of fluid in each pulsation is determined by the pressure inthe cylinder 28, which in turn depends on the setting of valve 89. Thispressure creates the force which tends to hold the pintle assembly inits down position. The storage limits of the accumulator, plus theamount of fuel replaced to the system while the pintle assembly leavesthe jets open will determine the range of volume released by anindividual burst. The volume built up in the accumulator and thepressure therein are roughly dependent upon each other in the flexibletype.

of accumulator shown. If the pressure in cylinder 28 is high, then theaccumulator pressure must be high to overcome it. This means that agreater volume will be stored in the accumulator while the pressure isbeing developed. Conversely, less pressure in the cylinder results in alesser pressure and volume in the accumulator. At least a part of theadditional increment in the accumulator passes through the jet at eachburst and thus the quantity of fuel in a burst is partly determined bythe pressure in cylinder 28.

Quantity control by the use of the spring-loaded device of Fig. 10 isthe same as that just described, except that the compressibility of thespring and the amount of its preloading are substituted for the fluidpressure in cylinder 28. The spring selected should be of suchcharacteristics that its resistive forces to the rise of the pintle donot build up with excessive rapidity, as it is compressed. Such anexcessive rise would diminish the snap action of the pintle when liftedoff the jet seat by increasing the force tending to seat the pintleassembly. A fluid pressure in cylinder 28 may be maintained constant,thereby exerting a constant downward load on the pintle assembly. Forthis reason, a pressurized gas is preferred to a spring.

This invention thus provides an automatic self-contained pulse typeinjector mechanism with one moving part. The actuating force may be thefuel pressure which is necessary for any fuel system, or some otherconvenient source of force. With so little in the way of moving parts,the device may be adapted to handle troublesome fuels such as moltenlithium, as well as other difficult substances. The controls are simpleand the fluid supply to the quantity control means (when used) existsonly as a pressure reservoir, from which there is little or noconsumption.

It will be appreciated that my invention is useful for the pulsatinginjection of fluids, including both liquids and gases, and is notlimited to liquid injection.

My invention is not to be construed as limited to the particularembodiments illustrated in the drawings and described in thedescription, which are given by way of illustration rather than oflimitation, and the invention is not limited except in accordance withthe scope of the appended claims.

I claim:

1. A pulse type injector pump comprising a body having a fuel chamber, afuel inlet to the chamber, a fuel injection jet from the chamber, and ashaft housing; a pintle assembly comprising a shaft having alongitudinal axis disposed in the shaft housing so as to be axiallyslidable therein and projecting into the chamber and toward the fuelinjection jet said shaft having a cross-section perpendicular to itslongitudinal axis which has an area larger than the injection jet,whereby the shaft can close the injection jet in one position of thepintle assembly; means for forcing the pintle assembly toward said onepintle position; an accumulator discharging into the fuel inlet; a fuelconduit interconnecting with the accumulator; and frequency controlvalving means in said conduit to regulate the flow of fuel to theaccumulator and fuel chamber; the shaft being proportioned in sizewhereby the area of a projection on a plane perpendicular to thelongitudinal axis of the shaft of the areas of the shaft facing theinjection jet and which are within the fuel chamber and exposed to fuelpressure when the pintle is in said one pintle position is greater thana projection on the same plane of areas of the shaft which face awayfrom the injection jet and which are exposed to the same conditions whenthe pintle assembly is in said one position; whereby opening of thefrequency control valving means permits fuel pressure and volume in theaccumulator and fuel chamber to rise, thereby lifting the pintleassembly from the aforementioned position and permitting discharge offuel through the injection jet, whereupon said discharge causes thepressure in the fuel chamber to fall, and the pintle again closes theinjection jet.

2. Apparatus according to claim 1 in which the means for forcing thepintle assembly to said one pintle position comprises springing means.

3. Apparatus according to claim 1 in which the means for forcing thepintle assembly to said one pintle position comprises a cylinder in thebody, a piston on the end of the shaft away from the injection jet anddisposed in the cylinder and valving means for regulating fluid pressure within the cylinder and upon the piston.

4. Apparatus according to claim 1 in which the accumulator has springingmeans for resisting accumulation of fuel.

References Cited in the file of this patent UNITED STATES PATENTS2,283,725 Eichelberg May 19, 1942 2,297,421 Lorenz Sept. 29, 1942FOREIGN PATENTS 611,604 France July 12, 1926

